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CHARACTERISTICS OF CHAT-ASPHALT FOR ROAD BASE APPLICATION
Nazimuddin M. Wasiuddin, Musharraf M. Zaman,
Robert W. Nairn, Nishad Kolothody ABSTRACT
More than 35 million cubic meters of mine chat, a waste material from abandoned lead and zinc
mining operations, are presently stockpiled at the Tar Creek Superfund Site. Currently, the Oklahoma Department of Transportation (ODOT) uses a
rather small percentage (about 20%) of washed (not raw) chat in hot mix asphalt (HMA). No systematic bench-scale tests, incorporating different
percentages of chat, have been performed previously for characterization of raw chat in HMA in an environmentally responsible manner. In order to
maximize the use of raw chat in chat-asphalt, three different base mixes having three different percentages of raw chat were prepared according to
the Superpave mix design methodology. It is observed that raw chat is an excellent source of aggregate in HMA for road base. As much as 50% raw chat
can be used in an S3-type Superpave base mix. Chat-asphalt mixes also did well in performance tests, namely moisture susceptibility, APA rut, and
permeability. A suite of environmental tests was performed to examine the leaching potential of heavy metals (lead, zinc, and cadmium) in
chat-asphalt due to dry and wet rut tests, and simulated milling. Test results indicate that chat-asphalt can be used safely as a roadway base.
RECOVERY OF PROTEINACEOUS MATERIALS FROM TANNED SOLID WASTES — YIELDS AND CHARACTERIZATION OF ISOLATED PRODUCTS
S. Tahiri
A. Albizane
M.R. Abargues, M. de la Guardia ABSTRACT
Tanned solid wastes have a highly organized structure in the form of fibers (Φ : 100nm) which
are very tight to each other. These wastes are formed mainly by proteins (75-79%). The amount of chromium oxide is about 4.4%. The alkaline
digestion of chromium tanned wastes to recover proteins products was studied using three alkaline agents: calcium hydroxide, sodium hydroxide and
sodium carbonate. The chrome cake was also recovered as co-product. Alkaline agent concentration and reaction time were chosen as parameters to
improve the process. The yields of the proteins products and material balances were calculated by weighing the isolated products throughout the
process and by determination of their physico-chemical characteristics. Proteinaceous materials from the three digestion procedures were analysed
using ICP-OES method for multielement determination and Ion Exchange Chromatography for inorganic anions analysis. The obtained results were
compared.
COMPARISON OF APPROACHES TO CHARACTERIZE THE UNIT WEIGHT OF MSW IN LANDFILLS
J.W.F. Morris, C.A. Lazarte, C.H. Pendleton, and R.D. Espinoza
R.C. Bachusb
K.H. Stokoe
A.M. Germain ABSTRACT
ABSTRACT
An evaluation of the unit weight of in-place waste at municipal solid waste landfill based on multiple field techniques is presented. The
composition and moisture content of the waste, as well as the presence of standing liquid were also investigated. The field investigations
consisted of spectral analysis of surface waves surveys, large-diameter bucket auger test borings, collection of bulk waste samples for waste
classification and laboratory analysis, small-diameter rotary auger test borings, cone penetrometer test soundings with pore pressure dissipation
measurements, and groundwater level measurement in gas wells. Data from existing in situ instrumentation and historical site records and surveys
were also used to estimate waste unit weight. Overall, the large diameter borings were considered to provide the best data for evaluating waste
unit weight. Values for waste unit weight and trends of unit weight with depth published in literature were used to complement and critically
evaluate findings from this investigation. Based on this, final recommendations for the variation of waste unit weight with depth at the site after
final construction, when the total depth of waste in place will likely exceed 75 m, were developed.
A COMPARATIVE STUDY OF THE ATTITUDE OF HOUSEHOLDS TOWARD RECYCLING OF SOLID WASTES
IN MALAYSIA AND VIETNAM — CASE STUDIES OF PENANG, MALAYSIA AND HO CHI MINH, VIETNAM
Abdelnaser Omran, Abdullah Mahmood
Hamidi Abdul Aziz
Tran Tuyet Mai ABSTRACT
Recycling of solid wastes is now recognized as the “most environmentally sound” strategy for
dealing with MSW following only the preventive strategy of source reduction and reuse. The main objective of the paper was, to gain information
about attitude of households toward recycling of solid wastes in Malaysia and Vietnam. The research involves administration of 600 survey
questionnaires to households in Penang, and in Ho Chi Minh City, of which 409 for Penang and 373 responses of Ho Chi Minh City respectively were
returned and analyzed. The result indicated that, if recycling is to be adequately developed as an effective alternative to landfill disposal,
public participation must be increased. The campaign focused too much emphasis on getting households to bring their recyclables to recycling
centers. The problem worsens because the number of collection centers is inadequate and cannot be easily located. The poor response is largely due
to the lack of facilities provided. Many residents are turned down when they are unable to locate the recycling centres and if they are able to
locate one, it seems too troublesome to be needed. A lesson from this study is that households attitude can be improved if adequate recycling
facilities are provided. These facilities must be strategically located and within easy reach so that the households are not unnecessarily
inconvenienced or discouraged to bring their recyclables. The Malaysia and Vietnam solid wastes recycling programme were found to be conflicting,
lacking in direction and funding. Clear goals and more awareness need to be established.
ARTIFICIAL NEURAL NETWORKS FOR ASSESSING WASTE GENERATION FACTORS AND FORECASTING WASTE GENERATION: A CASE STUDY OF CHILE
Eduardo Ordóñez-Ponce, M.E. (Nat Res)
Sandhya Samarasinghe, Ph.D.
Lynn Torgerson, B.E. ABSTRACT
One of the bottlenecks in implementing waste management policies in Chile is the lack of
information on factors correlating with waste generation. Recognising these factors is essential for implementing policies to reduce waste
generation.
UTILISATION OF WASTE PLASTIC BAGS IN BITUMINOUS MIX FOR IMPROVED PERFORMANCE OF ROADS
Adnan Qadir
Mansoor Imam
ABSTRACT
The quantity and type of waste being generated is growing at enormous rate. The plastic wastes
produced particularly in form of bags being non-degradable and with limited recycling options poses disposal problem. The probable solution as
mentioned lies in effective recycling of the waste which in fact is restricted by economic and operational constraints hence demanding a
sustainable solution for safe and ultimate disposal of waste plastic bags. An academic research aimed at probable use of waste plastic bags in
pavement structure so as to come up with an ultimate safe disposal together with improvement in the performance of pavement through better mix
design was undertaken. An aggregate material from waste plastic bags referred to as Recycled Plastic Waste Aggregate (RPWA) is developed which
would partially replace the conventional material to improve desired mechanical characteristics for a particular road mix. Preliminary
investigations have indicated that use of RPWA (1.2 – 3mm in size) in the surface and base mix design, when utilised up to 2.5% by weight
substitution has shown improved stability and flow (Marshall test) having unit weight and bulk specific gravity falling within the acceptable
limits for light and heavy traffic loads. It is envisaged that use of RPWA in the conventional asphalt hot mix design is likely to improve the
pavement performance with a sustainable solution for the disposal of plastic waste.
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